This invention relates to an improvement in helicopter designs for cargo carrying helicopters and in particular to a prop wash deflector for increasing the carrying capacity of such ships.
For many years helicopters have been used to move large or heavy objects by suspending the objects below the helicopter. In this way cargo can be carried to great heights quickly and safely. There are many examples of the use of helicopters in construction projects and even for erecting statues and other monuments.
Helicopters have also been used to bring material into remote locations, to map rugged terrain and in general to move cargo. In each instance equipment or cargo is suspended from the helicopter on pallets or the like.
It has been known for many years that the carrying capacity of a helicopter with a suspended cargo is not as high as would be expected. In other words, the carrying capacity is less than the theoretical number calculated based upon the thrust of the engine. While the carrying capacity also is affected by the number of passengers and cargo stored within the helicopter itself, the overall load affects fuel consumption and safety. Therefore it would be desirable to provide increased capacity with a given helicopter size and engine.
As is well known, the helicopter rotor generates a down draft which is responsible for lift. Impact of the down draft or prop wash on suspended cargo has the effect of forcing the helicopter to work against its self as the impact of this prop wash increases the effective weight of a suspended load.
Accordingly, there is a need to minimize the effect of prop wash on a suspended load.
In U.S. Pat. No. 5,927,649 there is described a suspendible carrier for a helicopter which is adapted to received multiple loads of cargo. The carrier includes a suspension assembly which is a platform which extends horizontally, onto which multiple cargo loads may be attached. The suspension assembly includes a skirt which extends downwardly and outwardly at an angle to the assembly. The skirt, however, is described as including a pair of side plates and a front plate that flare outwardly and is intended to guide a coupling assembly for cargo pickup. The suspension assembly is mounted to a cable which extends downwardly from the bottom of the helicopter. The skirt assembly, while it extends outwardly and downwardly, does not extend around the circumference of the suspension assembly and does not protect the assembly itself from prop down wash from the helicopter.
In U.S. Pat. No. 6,437,708 there is described a helicopter used for aerial land marking and surveying which has a suspended instrument pod which in turn has a conical housing surrounding instruments. While the conical housing does surround the instrument package, it in turn is supported by an external shell which is cylindrical. While the patent recognizes that it is desirable to have the operator of the equipment on the ground rather than in the helicopter in order to increase the capacity of the helicopter, there is no recognition that prop wash on the instrument package also would effect the carrying capacity of the helicopter.
Accordingly, there is a need for a structure attached to the helicopter for deflecting prop wash from suspended cargo to increase the carrying capacity and fuel economy.
It has been discovered that a skirt-like prop wash deflector can be mounted on a helicopter to deflect the prop wash from suspended cargo. The deflector of this invention in a preferred embodiment would be mounted integral to the helicopter chassis and extending outwardly from below the doors and over the helicopter skids or wheels so that prop wash would be deflected downwardly and outwardly from the helicopter chassis to thereby minimize the downward force of the prop wash on the helicopter itself, and eliminate its impact on suspended cargo.
Accordingly it is an object of this invention to provide a prop wash deflector to eliminate the impact of helicopter prop wash on suspended cargo.
It is another object of this invention to provide an integral deflector attached to the chassis of the helicopter for deflecting prop wash from the helicopters rotor away from the chassis of the helicopter, and for screening any suspended cargo.
It is yet another object of this invention to provide a deflector mounted on the chassis of a helicopter which is a plexiglass skirt which extends downwardly and outwardly from the helicopter chassis with a peripheral lip extending substantially horizontally and which covers any suspended cargo protecting the same from the prop wash generated by the helicopter rotor.
These and other objects will become readily apparent with reference to the drawings and following description wherein: